header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: 0.6s;
    padding: 40px 100px;
    z-index: 100000000;
}

header .sticly {
    padding: 5px 100px;
    background: #fff;
}

header .logo {
    position: relative;
    font-weight: 700;
    color: #fff;
    text-decoration: none;
    font-size: 4em;
    text-transform: uppercase;
    letter-spacing: 2px;
    transition: 0.6s;
}

header ul {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
}

header ul li {
    position: relative;
    list-style: none;
}

header ul li a {
    position: relative;
    margin: 0 15px;
    text-decoration: none;
    color: #fff;
    letter-spacing: 2px;
    font-weight: 500px;
    transition: 0.5s;
    font-size: 20px;
}

header.sticly .logo,
header.sticly ul li a {
    color: #000;
}